I’ve recently resolved an issue very similar to yours also involving an MCP23008 IO module. Please see my post for your reference:
Trouble with node-red node ncd MCP23008
Are you saying that you get both messages at the same time?
My experience was that I would only see one or the other. Regardless…on the surface it looks like the only difference between my situation and yours is that you are using I2C Version Set: 4 while I’m using I2C Version Set: 6. In any case it looks like the NcdSerialI2C.js driver has no support for any driver set above version: 3. My post explains how I was able to add a check for version 6 in the NcdSerialI2C.js file. Hopefully NCD will update their COM module soon and fix this issue. It’s not good for business.
Hope this helps.